Tagged With "gears"

Topic

5000 ton cooling Tower gear box

Ahmed Kabir ·
Will there be any substantial change in the oil level from its normal mark while running? In the cooling tower of international airport HVAC system, the level of oil found very low from its normal mark. I know that a small drop can happen from the normal mark while running. Will there be any considerable drop?  Could anybody can help me?
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5000 ton cooling tower gear box

Ahmed Kabir ·
Will there be any substantial drop in the oil level of gear box from its normal mark while it is running? This gear box with 200 HP Drive motor for 5000 ton chiller. While it is running the level of oil comes down to its lowest in the sight glass.  Could it be considerably lower from its normal oil level mark while running? Please help me. Kabir  
Topic

Constant Percentage Bandwidth spectrum

ALI HAIDERR ·
Dear Any body may please guide me how to analyze "Constant Percentage Bandwidth spectrum".I am using B&K system. Please find spectrum of gear box of compressor.
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Finish Mill Stand Gearboxes

Phil2425 ·
I am seeing a 1x vibration in our Finish Mill Stand Gearboxes. I know that a broken or cracked gear tooth will cause this issue, however we have opened up a box and did not see ay signs of a cracked or broken gear. Some of our other stands...
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High Vibration peak at 110Hz

Avinash Thawani ·
I am getting a high vibration peak at 110 Hz and it is there in the pump. The pump speed is 68Hz. This is a horizontal pump with a gear box between the motor and pump. Kindly advise what is the cause.
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High gear pump vibration

Alvaro Loayza ·
Hello to everybody, We have 6 ball mills in a cupper concentrator plant. These mills suport over two pad bearings (fixed and floating) that are lubricated with high pressure oil. Every mill has a lubrication room with two oil modules, one for each pad and works with high pressure Rickemeir gear pumps. Our problem is that almost all of these high pressure pumps have a very high level of vibration in some cases they reach 54 mm/s at GMF of pump gears. Do you suspect which could be the source...
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HIGH VIBRATION AT GEAR MESH FREQUENCY

dominich.vo ·
Hi all, please help me to diagnose one case about gearbox system. The system has been described in detail on attachment. The spectrum indicate high vibration at Gear mesh freq. (GMF) with harmonics and sideband of rotating speed. Base on spectrum data...
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GE frame 5 MS5001P Load Gear Quill Shaft Axial Movement

FSX ·
Hi every one We have a GE frame 5 Gas Turbine MS5001P coupled to Generator through reduction gear. Reduction gear is double helical. Pinion is coupled to turbine through gear type load coupling. Bull Gear shaft is hollow and a quill shaft is inserted in it. Generator Rotor is coupled to bull gear using quill shaft. Quill shaft has integral flange at generator end which is bolted to generator rotor flange. At the other end quill shaft has splines on outer dia and a hub with splines at inner...
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Gear tooth count selections

Rusty Cas ·
I monitor a double-reduction gearbox that has a 20 tooth high speed (1200 rpm) pinion, and a 34 tooth 1st intermediate gear.  Why would a designer use a combination like this with so many common factors? With the advanced milling machinery in use...
Topic

Very low level - Gear Box

Ahmed Kabir ·
This is for a cooling tower gear box with 200 HP drive motor. The oil level shows very low while running. I know that the level will be little down from normal in the sight glass outside the tower while running. How do we know how far it can go while running? Please help me. AK  
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Re: High gear pump vibration

Shurafa ·
It sounds like these are new (recently commissioned) equipment but with very high vibration. Despite the cause, I would recommend to involve the supplier/vendor/manufacturer/contractor responsible based on the contractual details. On the analysis side, it might be useful to take high resolution and high frequency vibration. High resolution plots may exhibit important components near the GMF. High frequency plots may exhibit orders or other higher frequencies this HTML class. Value is...
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Re: High gear pump vibration

Alvaro Loayza ·
Shurafa, Thank you very much for your reply. Well, we have already contacted Polysius for further information about these pumps problem. We are waiting for their response. These mills have been working for 6 months and all our measurements have been trended with a 1000 hz 6400 lor even with pump vibration points. So if my electric motor turns at 1780 RPM and the gear pump has 11 teeth, do you suggest a 300000 CPM fmax with high resolution ? About time behavior there isn't a significant...
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Re: Very low level - Gear Box

John from PA ·
As I had said previously in the thread you started at https://www.maintenance.org/top...0#406629055507039740 it is normal for the level to drop when you run the machine. You should determine if the OEM specifies the level with the machine shut down, running, or in a few instances both. If you fill the machine to the specified level with it not running, and then run it, that establishes the level while running. It really should not drop appreciably below that level. If it does continue...
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Re: Very low level - Gear Box

Ahmed Kabir ·
Thank you so much Mr. John. I am looking for OEM. Thank you once again, AK
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Re: Constant Percentage Bandwidth spectrum

John from PA ·
I suggest you go back and retake the data using narrow band analysis. When you do a constant percentage bandwidth spectrum the width of the filters is based on the full scale span. That isn't clear in your plot but I see components between 1 kHz and 10 kHz so perhaps it is 10 kHz?. You might also scale the horizontal axis linearly as opposed to the current logarithmic scaling. What you've done is more applicable to acoustic analysis.
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Re: Constant Percentage Bandwidth spectrum

ALI HAIDERR ·
Dear John, Thanks for your reply. Please give me some basic steps how to analyze CPB spectrum and how it works I am not familar with CPB
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Re: Constant Percentage Bandwidth spectrum

John from PA ·
As I said CPB is more applicable to acoustics, not machinery vibration. I suggest you read the content at http://azimadli.com/vibman/log...frequencyscaling.htm .
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Re: Constant Percentage Bandwidth spectrum

Walt Strong ·
Ali, Are you trying to use an old analyzer for machine vibrations? Constant percent filter has a varying filter bandwidth = x% x Center Frequency For example if percent is 6% then bandwidth at: 10-Hz = 0.6 Hz BW 100-Hz = 6.0 Hz BW 1000-Hz = 60.0 Hz BW 10,000-Hz = 600.0 Hz BW http://www.bksv.com/Library/Search%20Resources I Searched on "constant percent" for two results I think you will not find many folks who use this frequency analysis method for machine vibrations; except a few B&K...
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Re: Gear tooth count selections

John from PA ·
Originally Posted by John from PA: With the limited info you have provided, I would agree. But there may be some other issues forcing a tooth number selection. Cutting 19 teeth can be more of an issue than cutting 20, although both may require some special considerations to avoid tooth interference. If you go the other way, increase the number of teeth, then the pitch becomes finer and the ability of the tooth to sustain shock loading goes down. Can you provide a drawing (preferable) or...
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Re: Gear tooth count selections

Rusty Cas ·
My terminology is just what was used by others already on the job when I started 25 years ago. Input shaft was "high speed pinion shaft". 2nd shaft was "1st intermediate". Output shaft was called "output shaft. For a triple reduction, the 3rd shaft was called "2nd intermediate". So for consistency, the 2nd shaft was always called the "1st intermediate" even if there was no 2nd intermediate. Most plant people I've ever been around know next to nothing about the details of any gearbox. So I...
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Re: Gear tooth count selections

John from PA ·
Originally Posted by Rusty Cas: Forgive me John for not saying it properly. Is the proper terminology codified somewhere? I'm actually not certain if an AGMA Guideline exists on nomenclature. Having said that I would suspect that this most recent attachment would be what most AGMA member companies would follow. By the way, in my previous response, does the box with the non-hunting tooth combination have three or four gears (see my previous attachment)?
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Re: Gear tooth count selections

John from PA ·
Originally Posted by John from PA: Originally Posted by Rusty Cas: Forgive me John for not saying it properly. Is the proper terminology codified somewhere? By the way, in my previous response, does the box with the non-hunting tooth combination have three or four gears (see my previous attachment)? Rusty, you never replied to my question so let me provide some insight as to why I asked. If the gearbox has three rotors and three gears, i. e., one per shaft, then it is referred to as a simple...
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Re: 5000 ton cooling tower gear box

John from PA ·
Yes, it likely will come down in the oil level sight glass. You should determine if the OEM specifies the level with the machine shut down, running, or in a few instances both. The machines I have worked with have the oil level gage outside the tower and a means to add oil from a position outside the tower. How much it varies is a function of the specific gearbox so if your next question is to ask "how much lower will it be?", don't expect a reliable answer, just "guessestimations". By the...
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Re: 5000 ton cooling tower gear box

IrishMark ·
Link doesnt work John From PA
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Re: 5000 ton cooling tower gear box

John from PA ·
Seems erratic so try https://www.maintenance.org/for...ion-and-oil-analysis
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Re: GE frame 5 MS5001P Load Gear Quill Shaft Axial Movement

John from PA ·
Wow, old drawing (1973)! Some designs, and I can't speak directly to what you show on the specific drawing , take into account bore growth at speed. So what may be tight while static becomes line to line or slightly loose at speed.
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Re: High Vibration peak at 110Hz

Shurafa ·
I guess more data is needed to give a suggestion. Can you post a spectrum? Regards-Ali M. Al-Shurafa
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Re: High Vibration peak at 110Hz

Dan Timberlake ·
Hi Avinash, And post some history. And a picture of the installation, showing your measurement points. And some Time Wave Forms . And the pump make and model, with bearing part numbers if ball or roller. And spectra and TWFs from other pump and gearbox points. thanks Dan T
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Re: High Vibration peak at 110Hz

Avinash Thawani ·
Spectrum Attached
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Re: High Vibration peak at 110Hz

John from PA ·
Is that some form of 10X? At the top right of the plot I see "Max Amplitude 0.88 mm/s at 11.15 Hz." That would seem to refer to the peak on the extreme left. Gearbox tooth counts would be nice to have.
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Re: High Vibration peak at 110Hz

Avinash Thawani ·
Hi, That peak is Super synchronus peak is at 110Hz not 10x, the speed of the pump is 60Hz. The max amplitude peak is at 10Hz.
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Re: High Vibration peak at 110Hz

John from PA ·
I meant 10X of the 11.15 Hz (111.5 Hz) which as you likely are aware is very near the 110 Hz. What is causing the 11.15 Hz might be another area of investigation.
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Re: High Vibration peak at 110Hz

Shurafa ·
If this pump is not special, the vibration reading does not look high. In my practice and with the machines I deal with, I see many strange frequencies but I do not bother myself with investigating them if their amplitudes are "low". Assuming the pump is mounted on rolling element bearings, I would put a bearing defect on the list of the probable causes. Do you know the details of the bearings? Can you refresh the lubricant in the bearings (regrease/flush the oil) then take a new reading?
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Re: High Vibration peak at 110Hz

John from PA ·
LOL . In the very old days (late 1960's) many people adapted B&K equipment designed for acoustics to narrow band analysis. Since the equipment was designed for acoustics, the vertical scaling was often logarithmic creating a huge number of often meaningless peaks.
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Re: HIGH VIBRATION AT GEAR MESH FREQUENCY

John from PA ·
Originally Posted by dominich.vo: Hi all, please help me to diagnose one case about gearbox system. The system has been described in detail on attachment. The spectrum indicate high vibration at Gear mesh freq. (GMF) with harmonics and sideband of rotating speed. Base on spectrum data , can i judge the pinion gear has been wear or it is just a incorrect tooth meshing condition ? Your ideas will be appreciated Thanks a lot. First of all what are all your tooth combinations? In a case like...
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Re: HIGH VIBRATION AT GEAR MESH FREQUENCY

Becar ·
I would say there is too much clearance on the input bearings. The cause could be just incorrect settings or possible bearing/housing wear.
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Re: HIGH VIBRATION AT GEAR MESH FREQUENCY

dominich.vo ·
Hi John, we plan to open the cover of gearbox for visual checking. In recent overhaul, we changed pinion bearing of input shaft. It could be a problem of installation and result in high axial vibration. This gearbox is not in cooling tower so water comes inside gearbox could be eliminated. The temperature in gearbox also high ( >70oC)(Oil specification is carter SH 150). That means oil's quality also has problem. In my experience, the normal operating temperature is around 40 - 55oC .
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Re: HIGH VIBRATION AT GEAR MESH FREQUENCY

dominich.vo ·
Thanks Becar, I care about the pinion condition because if i can judge this gear's condition, I can plan to purchase the new one. It takes about 6 months to get them from the manufacturer. Just for your reference.
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Re: HIGH VIBRATION AT GEAR MESH FREQUENCY

John from PA ·
For Carter SH 150 70 deg C (158 deg F) should not be an issue. Based on what you have said, I would suspect that the bevel contact is not optimum. I would initate a check to verify the bevel settings and the proper setup of the bevel pinion bearings.
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Re: HIGH VIBRATION AT GEAR MESH FREQUENCY

BalancingVN ·
I see some peaks that I guess they are natural frequencies, so it could be worn or backlash. I think we need to see time waveform to confirm these.
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Re: HIGH VIBRATION AT GEAR MESH FREQUENCY

Chris184 ·
this reminds me of some similar looking data I collected on a 1:1 beveled gear set posted https://www.maintenance.org/top...isk-cold-saw-gearbox . I did end up finding a broken tooth.
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Re: Finish Mill Stand Gearboxes

John from PA ·
Can you post some data? The fact of the matter is it would be rare to see a gearbox that didn't have some 1X. Amplitudes matter. Have you investigated alignment issues, type of coupling and its behavior, etc. You might do better posting this in the vibration related forum at https://www.maintenance.org/for...on-alignment-balance
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Re: Finish Mill Stand Gearboxes

Phil2425 ·
The 1x impacts are visible in time domain. Spectral data does not show it as much.
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Re: Finish Mill Stand Gearboxes

Phil2425 ·
Here are the images. This data is taken in the vertical plane. Impacting is at the turning speed of the bottom pinion output shaft. This shaft has 2 gears on it. A 51T and a 28T gear. The 51T is the Bull that is driven by the input pinion from motor and the 28T mates up with a Top Pinion 28T and those drive the Rolls.
Topic

current fluctuation

raymundus ·
i have a problem related to current fluctuation in the Air Preheater motor, anyone know about the root cause of it? I have asked the electrical maintenance person, he said that the fluctuation is not caused by inverter of it. inverter has worked well. i have input information that this problem caused by gear box problem. but the problem is, the system is online so we are not posible to check it, i think we have to ensure if the problem is come from gear box by doing individual test. anyone...
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Re: current fluctuation

Walt Strong ·
Check if motor current has periodic fluctuations and compare period to preheater rotation speed. Preheater fouling or damage could cause unbalance or rubbing. Observe motor and gearbox vibrations by touch and measure vibrations and possibly contact ultrasound to detect any motor or gearbox faults. Walt
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Re: current fluctuation

Panta ·
It may be related with fluctuations of voltage on the motor. If the load is constant and temporary voltage drops to consequently reflect that motor must take more current .
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Re: current fluctuation

Walt Strong ·
My calculations with your data: Preheater speed: 1.11 rpm /60 = 0.019 Hz ~ 0.02 Hz Current amplitude frequency: 1/25 seconds = 0.04 Hz Conclusion: Current fluctuations are about 2x preheater speed (2 events per rotation), so possible air seal rub or other fouling/damage issues with preheater. "Can the gearbox abnormality checking be done by non-individual test." I am not sure what you mean by this question. No instruments are needed if for observation of gearbox vibrations and sound by touch...
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Re: current fluctuation

raymundus ·
In some sequence, the period of fluctuation is 25 seconds, the preheater speed is 1.14 rpm, i suppose that the period of fluctuation is the half of preheater period rotation. Can the gearbox abnormality checking be done by non-individual test. But i think, we don't have the tool
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Re: current fluctuation

raymundus ·
Yes, i have simple analysis related to my problem, the rotation speed is 1.14 rpm, so the period is approach to 52.63 s, the period of the fluctuation is 26 s, 1/2 rotation period. So i think that fluctuation is in the seal gap clearance that not properly adjusted. Radial seal is located on the 0, 180 and 230 degree...
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